Cam will seem smaller than described when in 489 cubes. That suggested RPM range is based around the cam being in a 454" engine....the addition of 35 more cubic inches is going to drop that rpm range right close to 400 rpm on the top end, and easily 250 rpm on the low end.
It's not a bad cam pick, just letting you know it will end up milder than catalog rating when used in the bigger engine.
If the range is then goot with you, go for it.

Hope you have a real rear axle in that Cutlass....the stock peewee 7.5" 10-bolt will be on borrowed time if it is still in there.

 

The rear end is still a 7.5 10bolt, but has a custom Auburn posi with 30 spline axles and richmond gears. I know, it's still on borrowed time, but hope it will last till I can get a 9 inch put in.

 

Looking at the flow numbers for the heads and comparing it to stock and big valve reworked stock iron ovals like the 781 the Brodix 270 is still well above those.

They'd swallow another 15 degrees of cam duration and still not be outpaced by the cam....probably even another 25 degrees but that would get into a pretty rowdy street engine territory.

 

Good info. I'm also wondering about the carburetor. I was thinking about an 850 vacuum secondary or a 750 mechanical.Gonna talk to Freakshow about a convertor. Any suggestions on how to carburate this thing?

 

for street use get the 750 carb.

 

I could go with either carb choice.
I do prefer vacuum's, but that is just me. They do take more time to get set-up and tuned correctly, and may need several tuning parts swapped from the as-delivered condition so if you don't already have a nice collection of Holley tuning parts it adds to your cost.

 

I guess I would agree. I'll look at an 850 vacuum secondary. I actually have quite a collection of Holley tuning parts because I spent a boat load of money on tuning my 770 Street Avenger vacuum secondary. Worked like crap till I spent a whole week tweaking and tuning it. Now it works great on my 408 BBC. I was looking at an FST performance RT-X series vacuum secondary 850 cfm carb but know nothing about these things. Are they Holley part compatible?

 

Yes, FST is just another fancy Holley clone. Tuning parts are the same.

 

If you’re not going to rev heaven, no need in a golly whomper, ground shaking cam.

I have the Howard’s 225/235 .589/.601 108 icl 112 lsa cam in mine. Same heads, compression, etc as well. Tire shredding torque, period. Has vacuum for power brakes, and not temperamental to drive. Sounds choppy at idle if you’re curious.

I have an 850 quick fuel black diamond ss carb, works great, but the 750 edelbrock that I started with worked far better for the street. Smaller carb and vac secondary means faster intake velocity which means off the line faster. I have 3000 stall fti converter, it’ll help the bigger carb.

However, the 750 gave out right at 5000rpms, the 850 doesn’t give out, but the cam does around 5700, just right for street driving and cast crank. So, 850 vac secondary Holley might be perfect or the edelbrock 800 avs.

Those heads are going to need back set rockers, at least mine did. The intake rocker nut would bottom out before correct pushrod length was achieved. I got mine from straub being I live close to them.

And if you have a power brake booster, get the cheater chrome valve covers, they clear the rockers and clear the booster. No need for the huge fabricated covers.

 

If you’re not going to rev heaven, no need in a golly whomper, ground shaking cam.

I have the Howard’s 225/235 .589/.601 108 icl 112 lsa cam in mine. Same heads, compression, etc as well. Tire shredding torque, period. Has vacuum for power brakes, and not temperamental to drive. Sounds choppy at idle if you’re curious.

I have an 850 quick fuel black diamond ss carb, works great, but the 750 edelbrock that I started with worked far better for the street. Smaller carb and vac secondary means faster intake velocity which means off the line faster. I have 3000 stall fti converter, it’ll help the bigger carb.

However, the 750 gave out right at 5000rpms, the 850 doesn’t give out, but the cam does around 5700, just right for street driving and cast crank. So, 850 vac secondary Holley might be perfect or the edelbrock 800 avs.

Those heads are going to need back set rockers, at least mine did. The intake rocker nut would bottom out before correct pushrod length was achieved. I got mine from straub being I live close to them.

And if you have a power brake booster, get the cheater chrome valve covers, they clear the rockers and clear the booster. No need for the huge fabricated covers.

Dfish, I was hoping you'd chime in! I knew what I am building is close to yours. I'm glad you like that cam. This kind of real world info I couldn't find because everybody tends to cam the crap out of their engines.

I have a 770 street avenger on my 408 right now. Might try that just for fun. There again people are putting 950s and up on their 489/496 engines. I mean, I get it, hero power looks great for bragging rights but how often do you see 6500 rpms on the street?

Forgive my ignorance, but what is a back set rocker? You're the first one I have read about with those heads that had rocker issues. What were the original rockers you tried using?

The power brake issue is a non issue. My Cutlass has a small booster from the factory and tall valve covers fit no problem.

I was looking at FTI convertors last night. Is yours an off the shelf 10" or a custom unit?

 

Backset rockers are made off center to make up the .100 difference in valve stem height. The race rites have .100” taller valve stems than stock. I tried scorpion rockers when I measured for pushrods. I used Scott Foxwell’s half lift method. You will need a super long checker push rod. JES-TOL-29400, that’s the jesel one I used, and 12” calipers. My rockers aren’t centered on the stem, but have a razor thin pattern, no issues after 12,000 miles of driving.

I used their 9.5” street racer converter, it’s around $650. It works awesome, it revs higher than a stock converter to pull out under normal driving, maybe 200-300 more rpms, takes all of 30 seconds to get used to. I’m still using the 8.2” 10 bolt 3.08 rear, engine is happy as can be, 3.42 will be like a rocket.

You could try the avenger, don’t be surprised if you have to jet up some. And be ready to put the orange pump cam in. You’ll lose about 1” idle vacuum going to an 850dp vs a 750 edelbrock carb. Have no idea about Holley vac secondary carbs in that size range. Mine isles at 700rpm in gear, 725 in park, doesn’t stink at idle, and picks up rpms real quick. Has 14” vacuum. Non lockup converter soaks up low rpm cruising bad manners bigger cams have.

Another thing will be oil pan, I have the moroso 20408 pan, had to notch the cross member for the pan corners to fit. The 20412(I think) has a shorter sump but it has the wings. So be prepared for that.

The clay smith cam from straub seems popular in these engines as well. So check it out as well. You’re going to be in for a shock in power difference, but don’t expect 10 second quarter mile times, the heads will do it, but your gonna have to twist it which gets real expensive real quick.

Oh yeah, use 5/8 spark plugs, 13/16 don’t fit.

 

Thank you very much for the info! What brand are your back set rockers? I am actually buying a complete set of pushrod checkers because I have several motors to do this winter. I will buy the 12 inch caliper.

I just got an email today from tsirace.com on a torque convertor recommendation. I gave them all the info I could and they have a 10 inch with a 2900 stall that they think would be perfect for my setup. Price is in the right range so gonna dig for comments on their stuff and snoop around.

I may just save up a few more bucks and just get an 850 vacuum secondary Holley. God knows I have enough tuning parts for them.

The oil pan I'm gonna use is a Milodon 30951. Techinspector actually recommended it to me on another thread. It's supposed to fit a G-body like a glove.

I have to admit I 'm having a hard time trying to wrap my head around the power this engine will produce. My 408 BBC is the most powerful engine I've ever owned, and it can get outta hand quick. When I was a teen I had a 1980 pinto I put a bored out 289 in it and that was a handful to drive but not much for torque. Building this 489 is completely unchartered territory for me.

Thanks for the heads up on the spark plugs!

 

I ordered the crankshaft yesterday and now I'm wondering a couple things. I had them do an internal balance job on it. Will that require more clearance in the block for the counter weights? Scat also said I would have to run 6.385 rods which I have, I'm guessing that is also due to counter weight clearance? I did internal balance for the ease of reusing my flexplate and balancer. Didn't really think about how that affects the crankshaft. Did I just make a mistake? This was crazy expensive in my opinion, so want to make sure it's done right.

 

No more clearancing than normal for a stroker...it is the connecting rod nut area of the rod that comes closest to the pan rails(or bolt head on a capscrew rod), and the hip/original bolt head area of stock rods to bottom of cylinder barrels where clearancing is needed....many capscrew rods eliminate all or most of the clearancing needed.

Counterweights generally aren't a problem except mixing rod lengths and ending up with counterweights hitting the underside of the piston at Bottom Dead Center. The 6.385" rod is used for that reason.

 

Thank you eric. That eases my mind quite a bit. The thing I'm still aching from though is the price! I wanted just a cast crank done up since they can handle 800 horse, and Scat bent me over to the tune of 700bucks to balance it. I thought this was high but then again I've never had one balanced before.
This friggin 489 is costing me an arm, a leg and possibly a testicle lol

 

Balancer and flex plate seem cheaper, lol.

You’ll have fun once it’s in, big block=big bucks.

 

Update:
I finally got my crankshaft from Scat. This is a nice piece of work! The only thing I'm not sure about is the mallory slugs in the crank are pressed in but not welded in. Is this a concern at all? Also, they sent me King bearings. I have never used them, they're a good bearing, right?

Things have changed quite a bit since I started collecting parts for this engine. The 1984 Cutlass it was going to go in has since been retired due to frame rot. The new candidate is a 1980 Chevy El Camino. Here's the thing, The car is pretty nice and had a repaint about ten years ago. I don't want to butcher this car up. Is it possible to get this engine to fit under the hood?

 

if the hole for the Mallory was drilled along the longitudinal axis then welding is not required